Phosphate is an element that occurs naturally as a crystalline compound, mostly as hydroxyapatite in the bones and teeth of humans and other mammals. It is also an important nutrient in plants, being used for the growth of roots and leaves. In biological systems, phosphates can be found as free phosphorus anions in solutions (inorganic phosphates) or bound to organic molecules as organophosphates.
Rubidium zinc hydrogen phosphate, Rb2Zn2(HPO4)3, is a new crystalline material prepared by an unusual method utilizing long nucleation times and the reversible formation of tetragonal crystals. It is a polymorph of the double salt Zr(HPO/sub 4/)Zn(HPO/sub 2/4/)P2O5, which has one central phosphorus atom surrounded by four oxygen atoms in a tetrahedral structure.
The structural characteristics and electrical properties of rubidium titanyl phosphate (RbTiOPO4, RTP) large single crystals have been investigated by measuring dielectric constants, dispersions, impedances, conductivities and pyroelectric coefficients. The results show that the phosphate glass exhibits a displacive-type ferroelectric phase transition with temperature 829 + 1degC.
A comparison of the kinetics of the transport of radioactive rubidium ions Rb86 and P32 orthophosphate anions across isolated rabbit mesentery shows that the transfer of both tracers is mediated by passive diffusion, in accordance with earlier findings for the same system. The addition of atropine accelerates the transfer rate, but does not significantly reduce it. This is consistent with the observation that at low temperatures and pH values, no carrier mechanism is operating.